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From: Richard Cochran <richardcochran@gmail.com>
To: John Stultz <john.stultz@linaro.org>
Cc: linux-kernel@vger.kernel.org, Prarit Bhargava <prarit@redhat.com>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	Jan Kara <jack@suse.cz>, Jiri Bohac <jbohac@suse.cz>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH 4/5] ntp: Do leapsecond adjustment in adjtimex read path
Date: Fri, 12 Jun 2015 09:37:11 +0200	[thread overview]
Message-ID: <20150612073711.GA1844@localhost.localdomain> (raw)
In-Reply-To: <1434063297-28657-5-git-send-email-john.stultz@linaro.org>

John,

The description is just awful.

On Thu, Jun 11, 2015 at 03:54:56PM -0700, John Stultz wrote:
> Since the leapsecond is applied at tick-time, this
> means there is a small window of time at the start
> of a leap-second where we cross into the next second
> before applying the leap.

First you say the leap second is applied at the tick, ...
 
> This patch modified adjtimex so that the leap-second
> is applied on the second edge. Providing more correct
> leapsecond behavior.

and then you say it is applied on the edge of the second.

Instead, this second paragraph should say:

   This patch modifies adjtimex to apply the leap second
   correction to the returned time value.  Callers of adjtimex
   will observe the leap second occuring exactly on the edge
   of the second.

> This does make it so that adjtimex()'s returned time
> values can be inconsistent with time values read from
> gettimeofday() or clock_gettime(CLOCK_REALTIME,...)
> for a brief period of one tick at the leapsecond.

How about this instead?

   As as a result, adjtimex()'s returned time values will be
   inconsistent with time values read from gettimeofday() or
   clock_gettime(CLOCK_REALTIME,...) for a brief period of one
   tick at the leapsecond.

Thanks,
Richard

  reply	other threads:[~2015-06-12  7:37 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-11 22:54 [PATCH 0/5 v2] Fixes for leapsecond expiring early ABS_TIME CLOCK_REALTIME timers John Stultz
2015-06-11 22:54 ` [PATCH 1/5] time: Move clock_was_set_seq update to before we update the shadow-timekeeper John Stultz
2015-06-12  9:31   ` [tip:timers/core] time: Move clock_was_set_seq update before updating shadow-timekeeper tip-bot for John Stultz
2015-06-11 22:54 ` [PATCH 2/5] ntp: Introduce and use SECS_PER_DAY macro instead of 86400 John Stultz
2015-06-12  9:31   ` [tip:timers/core] " tip-bot for John Stultz
2015-06-11 22:54 ` [PATCH 3/5] time: Do leapsecond adjustment to avoid early timer expirations John Stultz
2015-06-12  9:32   ` [tip:timers/core] time: Prevent early expiry of hrtimers[ CLOCK_REALTIME] at the leap second edge tip-bot for John Stultz
2015-06-11 22:54 ` [PATCH 4/5] ntp: Do leapsecond adjustment in adjtimex read path John Stultz
2015-06-12  7:37   ` Richard Cochran [this message]
2015-06-12  9:32   ` [tip:timers/core] " tip-bot for John Stultz
2015-06-11 22:54 ` [PATCH 5/5] selftests: timers: Add leap-second timer edge testing to leap-a-day.c John Stultz
2015-06-12  9:32   ` [tip:timers/core] " tip-bot for John Stultz
2015-06-12 14:52 ` [PATCH 0/5 v2] Fixes for leapsecond expiring early ABS_TIME CLOCK_REALTIME timers Dave Jones
2015-06-12 14:55   ` Prarit Bhargava
2015-06-12 14:59     ` Dave Jones
2015-06-12 15:02       ` Prarit Bhargava
2015-06-12 17:58   ` John Stultz
2015-06-12 18:06     ` John Stultz
2015-06-12 18:11       ` Thomas Gleixner
2015-06-13  7:17         ` Ingo Molnar
2015-06-15 13:10 ` Prarit Bhargava
2015-06-15 13:46   ` Prarit Bhargava
2015-06-15 18:55     ` John Stultz

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